1. Field of the Invention
This invention relates to secure operation of processing devices. More particularly, the invention relates to a secure system manager distinct from and with priority over the operating system so as to control inputs to, outputs from, and commands executed by the device.
2. Description of Related Art
Processing devices are often managed by broadly-accessible general support programs, sometimes referred to as “operating systems”. An operating system typically manages resources, controls many device operating functions, and communicates with and supports other programs.
An operating system is most useful when it supports and/or communicates with a broad range of other programs. If an operating system won't “talk to” a program, the support features of the operating system are not available to that program, and the device may not be able to use the program.
However, an operating system that is broadly accessible is also broadly vulnerable. Programs may be written that perform functions that are undesirable and/or illegal, while still being technically valid programs. Such programs may take advantage of an operating system's broad accessibility to access the operating system itself, other programs, stored data, etc.
In view of these matters, a need exists for a better method and apparatus for securing processing devices.